/*
 * Copyright 2007 Rob Nielsen
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * 	http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.googlecode.proxymatic.apps.data.handlers;

import com.googlecode.proxymatic.apps.data.FieldNameCalculator;
import com.googlecode.proxymatic.core.AbstractMethodHandler;
import com.googlecode.proxymatic.core.BuildtimeContext;
import com.googlecode.proxymatic.core.MethodInvoker;
import com.googlecode.proxymatic.core.ProxyBuilder;
import com.googlecode.proxymatic.core.RuntimeContext;
import com.googlecode.proxymatic.core.util.PrimitiveUtil;
import com.googlecode.proxymatic.core.util.ReflectUtil;

import java.lang.reflect.Method;
import java.util.Map;

public class DataAccessMethodHandler extends AbstractMethodHandler implements MethodInvoker {
    public MethodInvoker getInvoker(Method method, BuildtimeContext context, ProxyBuilder proxyBuilder) {
        if ((method.getName().startsWith("get") ||
                (method.getName().startsWith("is") && method.getReturnType().equals(boolean.class))) && method.getParameterTypes().length == 0) {
            return this;
        }
        return NOT_HANDLED;
    }

    public Object invoke(Method method, Object[] parameters, RuntimeContext context) throws Throwable {
        Map backingMap = (Map) context.getImplementationObject(0);
        FieldNameCalculator fieldNameCalculator = (FieldNameCalculator) context.getImplementationObject(1);
        String key = fieldNameCalculator.getBackingMapKeyName(method);
        Object returnValue = backingMap.get(key);
        Class returnType = method.getReturnType();
        if (returnValue == null) {
            if (returnType.isPrimitive()) {
                return PrimitiveUtil.getDefaultInstance(returnType);
            }
        } else {
            Class cla = returnType;
            if (cla.isPrimitive()) {
                cla = PrimitiveUtil.getDefaultInstance(cla).getClass();
            }
            // FIX ROB Dup with DataFactory
            if (!ReflectUtil.isInstanceOrBoxed(returnType, returnValue)) {
                throw new IllegalStateException("Invalid object in backing map for field '" + key + "'. Expected " + returnType + " but got '" + returnValue + "' (" + returnValue.getClass() + ")");
            }
        }
        return returnValue;
    }

    public Class[] getExceptionTypes() {
        return NO_DECLARED_EXCEPTIONS;
    }
}
